The verse 11 of Sura Tarik
in the Qur'an, refers to the "returning" function of the
sky.

"By Heaven with its cyclical systems."
(The Qur'an, 86:11)

This word interpreted as "cyclical" in Qur'an
translations also has meanings of "sending back" or "returning".

As known, the atmosphere surrounding the Earth consists
of many layers. Each layer serves an important purpose for the benefit
of life. Research has revealed that these layers have the function
of turning the materials or rays they are exposed to back into space
or back down to the Earth. Now let us examine with a few examples
of this "recycling" function of the layers encircling
the Earth.

The troposphere, 13 to 15 kilometers above the Earth,
enables water vapor rising from the surface of the Earth to be condensed
and turn back as rain.

The ozone layer, at an altitude of 25 kilometers, reflects
harmful radiation and ultraviolet light coming from space and turns
both back into space.

The ionosphere, reflects radio waves broadcast
from the Earth back down to different parts of the world,
just like a passive communications satellite, and thus makes wireless
communication, radio, and television broadcasting possible over
long distances.

The magnetosphere layer turns the harmful radioactive
particles emitted by the Sun and other stars back into space
before they reach the Earth.

The fact that this property of the atmosphere's layers,
that was onlt demonstrated in the recent past was announced centuries
ago in the Qur'an, once again demonstrates that the Qur'an is the
word of God.

The presence of water is essential for life
on Earth. One of the factors acting in the formation of water
is the Troposphere, one of the layers of the atmosphere. The
troposphere layer enables water vapour rising from the surface
of the Earth to be condensed and turn back down to the Earth
as rain.

The atmosphere layer that blocks the rays
that might be fatal to life on Earth is the Ozonosphere. The
Ozonosphere turns harmful cosmic rays like ultraviolet back
to space, hence preventing them from reaching the Earth and
harming life.

Each layer of the atmosphere has beneficial
attributes for human beings. The Ionosphere layer, one of
the upper layers of the atmosphere, for example, reflects
radio waves broadcast from a certain centre back down to the
Earth, thus enabling broadcasts to be received from long distances.